In Dark Heresy, the players assume the roles of Acolytes working for an Inquisitor, who sends them on various missions. Depending on the type of mission, gameplay can involve investigation, combat, intrigue, or other genres. The Game Master is able to tailor their campaign to suit their player group through this flexibility. Since the players work for an Inquisitor, most missions involve rooting out heresies or matters relating to them. The game allows for many other missions, including wiping out dangerous gangs, gathering evidence of corruption, dealing with alien threats or eliminating rogue psykers.[3]
In Rogue Trader, players take the role of a Rogue Trader and their crew as they operate outside the stellar and legal boundaries of the Imperium of Man (Imperium). The book provides, among other things, rules for interplanetary commerce and spaceship operation, travel, combat, and customization.[4]
In Deathwatch, players take the role of surgically modified super humans known as Space Marines. These individuals are recruited from their native Chapters (fighting units of approximately 1,000 people) to serve as a military arm of the Inquisition, against particularly dangerous heretics known as Chaos worshipers and alien lifeforms known as Xenos.[5]
In Black Crusade, players take the role of Chaos-corrupted characters. Black Crusade, essentially, is the corrupted version of previously mentioned Warhammer 40,000 roleplaying games. Characters are cast in the role of the villain, with the players actively working against the Imperium and for the forces of Chaos in the sector.[6]
In Only War, each player takes the role of an Imperial Guardsman, one of the billions of hardened conscripts constantly fighting on myriad fronts at the whim of the Earth-based government of the Imperium (Adeptus Terra).[7]
Black Industries chose to set Dark Heresy in a previously unknown sector of the game's fantasy universe, the Calixis Sector, within the Segmentum Obscurus. This sector lies adjacent to Scarus Sector, which is the setting of Dan Abnett's Eisenhorn trilogy. Calixis is similarly adjacent to the Koronus Expanse, the setting of Rogue Trader, and to the warzone on the edge of the Periphery Sub-Sector, the setting of Only War.
